This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Vermiculite historically extracted from the Libby, MT mine was contaminated with a toxic form of naturally-occurring fibrous and asbestiform amphibole occurring in veins throughout the deposit. It has recently been discovered that tree bark samples collected within the EPA restricted mine area, within the town of Libby, and along the railroad corridor west of town also contain varying levels of amphibole contamination. This COBRE subproject is composed of three separate Specific Aims. Through the analysis of bark samples coupled with the analysis of meteorological data, Aim 1 will determine the extent of contamination at varying distances from the mine site. This Aim will enable the EPA and health investigators at the Center for Environmental Health Sciences to focus and refine their efforts by identifying where the asbestos plume was distributed throughout the area. Results of Aim 1 could identify new "hot spots" that have not yet been discovered, possibly averting future asbestos exposures, while also determining safe areas for firewood harvesting. Aim 2 will address what happens to amphibole fibers when contaminated wood is burned during residential home heating, and determine if the inhabitants of the Libby valley are (potentially) currently being exposed to asbestos through wood stove use, the most common form of residential home heating in Libby. Aim 2 will also provide immediate feedback to residents regarding potential risks in burning contaminated firewood, having an impact in communities well beyond Libby. Through the analysis of bark samples from trees in proximity to railroad corridors, Aim 3 will determine the extent of asbestos contamination in specific railroad corridors (from Spokane, WA to Libby to Great Falls, MT) originating from Libby in order to recreate the historical exposure path. It is hoped that the results generated in Aim 3 will prevent future exposures to those that reside and work along these corridors.